lands92的专栏

问题来源：https://oj.leetcode.com/problems/reverse-words-in-a-string/ Given an input string, reverse the string word by word. For example, Given s = "the sky is blue", return "blue is sky the".

1.LeetCode 89题 Gray Code public List grayCode2(int n) { List result = new LinkedList<>(); for (int i = 0; i < 1 << n; i++){ result.add(i ^ i >> 1); } return result; } 2.LeetCode 136题 Single Nu

1 Two Sum    求数组中等于target的两个数的下标 数组 O(n*n) O(n)，用HashMap存已遍历部分 2 Add Two Numbers 两数相加，数用链表表示，低位在头，高位在尾 链表 当l1、l2不为空或tmp不为0时，依次相加，得到tmp，tmp%10即当前位，tmp/10为进位 3 Longest Substring With